Using TAR to restore file from LTO tape drive to mount point directory

I created a backup tape using tar -cvf /dev/rmt1 /filesystem1 and taken 2 more filesystems ( /filesystem2, /filesystem3) using tar -uvf /dev/rmt1 /mountpoint, now am trying to restore single directory from filesystem1 from tape drive using xvf ...but it doesn't happen, its restores all data in the tape drive,

Can any one help me to restore particular directory from tape to mountpoint.

Be aware that you may need to rewind the tape again to retrieve your file
after testing the tar file on tape.
I hope that you are using a no rewind driver when you wrote the three
separate file systems to separate tar files to begin with.

I did some further checking and the -u option should not be used on a tape
device. This is from the man pages of tar.
1 When the storage device is an ordinary file or a block special
file, the -u and -r flags backspace. However, raw magnetic tape
devices do not support backspacing. So when the storage device
is
a raw magnetic tape, the -u and -r flags rewind the tape, open
it,
and then read it again.
2 Records are one block long on block magnetic tape, but they are
typically less than half as dense on raw magnetic tape. As a
result, although a blocked raw tape must be read twice, the
total
amount of tape motion is less than when reading one-block
records
from a block magnetic tape once.
3 The structure of a streaming tape device does not support the
addition of information at the end of a tape. Consequently when
the storage device is a streaming tape, the -u and -r flags are
not valid options.

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